Convenience outlet with protective rotating shutters



June 26, 1956 G. B. BENANDER 2,752,581

CONVENIENCE OUTLET WITH PROTECTIVE ROTATING SHUTTERS Filed March 30, 1955 [)7 1 6)) t or: George .5. B enanaer,

H's Ator'nqy United States Patent CONVENIENCE OUTLET WITH PROTECTIVE ROTATING SHUTTERS George B. Benander, Oaklawn, R. I., assignor to Genera: Electric Company, a corporation of New York Application March 30, 1955, Serial No. 497,903

6 Claims. (Cl. 339--41) The present invention relates to convenience outlets, and in particular to an adjustable torsion spring means in cooperation with the protective rotating shutters which normally close the attachment prong-receiving slots in the front face of the outlet.

In the home, convenience outlets are usually located in the walls about 12 inches above the floor so that they naturally attract the attention of small children and especially those in the crawling stage who are interested in exploring the world around them. Electric lamps, clocks and radios are usually arranged in the home in order to satisfy the decorative taste of the occupants without relation to the location of the available convenience outlets. Consequently, extension cords have found wide usage in the home in order to connect the various electrical appliances with the usually inadequate wiring system of the home. When the attachment plugs of these extension cords are connected in the outlets, there is relatively little danger that a child will become injured thereby, but the most serious danger is present when the outlet is unoccupied by attachment plugs, for then a child might use a hairpin, scissors or a bare wire to poke into the outlet. If the child is standing near a radiator, a water pipe or similar grounded object, he might receive a serious electrical shock or start a fire.

While it is not new in'the art of wiring devices to provide a convenience outlet with protective rotating shutters, it is felt that the present invention is a definite step forward in the art for it includes an improved adjustable torsion spring means for actuating the rotating shutters to normally bias the prong-receiving slots in the shutters 90 out of alignment with the prong-receiving slotsin the front face of the outlet. One end of the torsion spring is engaged with a portion of the rotating shutter and moves therewith, while the opposite end is seated in a cross-shaped opening in the back cover plate of the outlet. Thus, it is possible to assemble the outlet without applying any torsion action to the spring which contributes to the ease of assembling the different parts of the outlet within the hollow housing. One, the contact members and torsion springs are placed in the housing, the back cover plate and mounting strap are then added to complete the assembly. The only step remaining is to apply a suitable spring tension to the torsion spring which is effected by first depressing the end of the spring seated in the cross-shaped opening. Once the spring is freed from the opening, the spring is turned the necessary amount to an adjacent cross arm of the opening. Then by releasing the spring it will again be seated in the opening and ready for operation. By this simple maneuver, it is possible to provide the rotating shutter with a highly dependable and positive action torsion spring with the least amount of complication and effort.

The principal object of this invention is to provide a convenience outlet with a protective rotating shutter over the prong-receiving openings therein by utilizing an adjustable torsion spring for normally biasing the prongice receiving slots in the shutter out of alignment with the similar slots in the outlet.

A further object of this invention is to provide a convenience outlet with protective rotating shutters by incorporating a torsion spring connected at one end to the shutter while the opposite end is seated in a cross-shaped opening at the back of the outlet so that the tension of the spring may be adjusted after the outlet is completely assembled.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Figure l is a front view of a convenience outlet provided with protective rotating shutters of a type embodying my invention with the lower shutter removed to show the details of construction of the front face of the outlet.

Figure 2 is a right side view of the convenience outlet of Figure 1 with the lower rotating shutter in place and a partial sectional view taken at the lower end on the longitudinal axis of the outlet.

Figure 3 is a back view of the outlet of Figure 2 with a portion of the mounting strap and back cover plate removed to show the details of construction of the interior of the outlet.

Figure 4 is an exploded perspective view of a convenience outlet having protective rotating shutters embodying my invention.

Referring in detail to the drawing, Figure 4 shows a convenience outlet 10 embodying my invention comprising a recessed body member 11 which may be made of any suitable molded insulating material. The front face of the body member 11 is provided with a pair of circular depressions 12 in each of which are located a pair of attachment prong-receiving slots 13. Looking at Figure 3, it will be seen that the body member 11 is provided with longitudinally extending recesses 14 at each side of the outlet for receiving the contact members 15. These particular contact members have inclined ends 16 which overlie the slots 13 in the front face of the body memher for making electrical connection with the prongs of attachment plugs to be inserted therethrough. The contact members 15, as shown, are of novel construction in having air of ianced tongues 1! which are doubled back on themselves to underlie the head of the terminal screw 18 which is disposed therebetween. When screw 18 is threaded into the tapped opening 19 in the contact member and a bare wire is inserted under one or both of the lanced members 17, the downward force of the head of the screw 18 will crimp the lanced member 17 into good mechanical and electrical connection with the bare wires. The invention of this contact design is being claimed in a copending application, Serial No. 386,558, which is assigned to the same assignee as is the present invention and issued on November 8, 1955, as Patent No. 2,723,385.

A central bore 20 is formed in the circular depression 12 between the slots 13 to communicate with the interior of the body member 11. A rotating shutter 21 of a similar size as the circular depression 12 is provided with a pair of prong-receiving slots 22 for cooperation with the similar slots 13 in the front face of the body member 11. An apertured stud 23 with internal threads is located on the bottom of the shutter 21 to lie within the central bore 24). An arcuate groove 24 is arranged in the depression 12 near the outer edge thereof for receiving a stop means 25 also formed on the bottom side of the shutter 21. The arcuate groove 24 is of such a length that when the stop 25 is located therein, the shutter may move approximately before the stop 25 strikes the ends of the groove 24. As seen in Figures 3 and 4, a self-tapping screw means 28 is inserted from the back of the body member 11 to thread into the apertured stud 23 of the shutter 21 so that the shutter is mounted in the body member to rotate hrough an angle of 90. This screw 28 has a slotted head for receiving'one end 29 of the torsion spring 30. The opposite end 31 of the spring is rounded to form a longitudinally extending tongue that is adapted to seat in the cross-shaped opening 32 formed in the insulating back cover plate 33 which is of fiberboard material. This feature is best shown in Figure 2 of the drawing.

Since the recessed body member 11 has an open back, it is provided with the cover plate 33 which is held in place by a metal mounting strap 34, as best shown in Figure 4 of the drawing. The cover plate 33 has a rectangular-shaped slot 35 for receiving the lanced member 36 of the mounting strap. In the assembled view of Figure 2 it will be seen that the lanced member 36 extends through the cover plate 33 and entirely through the body member 11 so that the free end of the member 36 may be bent to lie against the front face of the outlet to serve as the final assembly means, thereby eliminating the usual fastening screws provided in other known'types of convenience outlets. This particular novel means for holding the outlet in an assembled relation is taught by the Benander Patent No. 2,695,392 which is assigned to the same assignee as is the present invention. Considering again the back cover plate 33 of Figure 4 of the drawing, there are a series of four conductor-receiving openings 40 arranged on the opposite side edges of the plate. Thus, the outlet of the present invention may be wired from the back by insetring bare wires through the openings 40 and under the lanced tongues 17 formed on the contact members 15.

To assemble the convenience outlet of the present invention, it is first necessary to attach the rotating shutters 21 in the circular depressions 12 of the front face of the body member 11 by means of the screws 28 which are inserted through the back opening in the body member 11. Then, the pair of contact members are placed in the parallel longitudinally-extending recesses 14 in the back of the body member 11, and the torsion springs 30 are placed on top of the slotted head of each of the fastening screws 28. Finally, the back cover plate 33 and mounting strap 34 are used to close the back of the body member and the free end of the lanced member 36 of the mounting strap is bent over, as best seen in Figure 2, as a final step in assembling this device. Then it is possible to provide the torsion spring 30 with the proper tension by using a special tool such as a thin rod (not shown) having a bifurcated end for depressing the end 31 of the spring until it is free of the cross-shaped opening 32 in the cover member 33 and then by twisting the spring in the proper direction 45 or 90 as the case may be. The tool is finally Withdrawn from the outlet so that the end 31 of the spring will again be seated in one of the cross arms of the opening 32.

One important advantage of the present invention is the fact that the adjustable torsion spring 30 is not tensioned during the assembly of the parts in the outlet. It will' be appreciated by one skilled in this art that it is often rather difficult to compress or tension a spring and fit it into a small space between mating parts. Oftentimes, the spring will slip and due to the energy stored therein, will fly across the room and become lost. The present invention has been used to eliminate this difliculty and has contributed to the development of a convenience outlet having protective rotating shutters which is simple in design, having a minimum number of parts as well as being easy to assemble quickly on a mass production basis while being reliable in operation over a long life span.

It will also be appreciated by those skilled in this art that while I have elected to illustrate my invention as it may be used in a convenience outlet, it is deemed obvious that the same invention may be used in a tap for an extension cord that has protective rotating shutters, as

well as in an adapter that may be fastened over existing convenience outlets so as to provide it with the safety feature of the present invention.

Modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an outlet for electric wiring systems comprising a body member and .a cover member assembled together to form a hollow housing, said housing having at least one circular depression in its front face, and a pair of slots formed in said depression for receiving the prongs of an attachment plug, the interior of said housing having recesses in alignment with the said slots, contact members positioned in said recesses and adapted to make connection with the said prongs, a central bore formed in said circular depression between the said slots, a rotating shutter having a similar pair of prong-receiving slots positioned in said depression and having an apertured stud held in the said central bore by a suitable fastening means, a stop means for limiting the rotation of the shutter to approximately the invention comprising an adjustable torsion spring having one end secured to the fastening means of the rotating shutter to rotate therewith while the opposite end extends diagonally across the spring and is shaped to be seated in a cross-shaped opening in the back wall of the housing whereby the proper spring tension may be adjusted after the outlet is completely assembled so that the slots in the shutter are normally spring biased to be 90 out of alignment with the prong-receiving slots in the front face of the body member.

2. In an outlet for electric wiring systems comprising a hollow housing having at least two attachment prongreceiving slots in the front face thereof, the interior of said housing having recesses in alignment with said slots, and contact members positioned in said recesses and adapted to make connection with the said prongs, a rotating shutter fastened on the front face of the outlet and having attachment prong-receiving slots similar to those on the front face of the outlet, a stop means for limiting the rotation of the shutter to approximately 90", an adjustable torsion spring having its longitudinal axis arranged along the pivotal axis of the rotating shutter with one end of the spring fixed to the shutter while the opposite end within a slotted opening in the back wall of the outlet whereby the proper spring tension may be adjusted after the outlet is completely assembled so that the slots in the shutter are normally spring biased to be 90 out of alignment with the prong-receiving slots in the front face of the outlet.

3. In an outlet as recited in claim 2 wherein the rotating shutter is provided. with a central apertured stud which extends into a bore in the front face of the outlet, and a fastening screw is used for assembling the shutter to the outlet, the said fastening screw having a slotted head for receiving one end of the said torsion spring while the opposite rounded end of the spring engages in a cross-shaped opening in the back wall of the outlet.

4. In an outlet for electric wiring systems comprising a hollow housing having a group of attachment prongreceiving slots in the front face thereof and a rotating shutter pivotally supported on the front face of the outlet and having a group of attachment prong-receiving slots similar to those on the front face of the outlet, a stop means for limiting the rotation of the shutter to an acute angle, an adjustable torsion spring connected at one end to the said rotating shutter adjacent its pivotal axis and at its opposite end in a slotted opening through the back wall of the outlet, whereby the proper spring tension may be obtained after the outlet is completely assembled by depressing the spring so that it is freed from the opening in the back wall of the outlet and turning it the proper amount so that it may be released to again seat within the opening in the back wall of the outlet.

5. In an outlet for electric wiring systems comprising a hollow housing for enclosing the contact members, the front face of the outlet having at least two attachment prong-receiving slots, and means for pivotally mounting a protective shutter over the front face of said slots, means for limiting the angle of movement of said shutter, and slots formed in said shutter to conform with the beforementioned slots, and a coil spring arranged within the housing on the pivotal axis of the said shutter with one end connected to the shutter While the opposite end has a longitudinally extending tongue that is seated in a slotted opening through the back wall of the housing, whereby the proper spring tension may be applied to the spring after the outlet is completely assembled so that the slots in the shutter are normally spring biased out of alignment with the prong-receiving slots in the front face of the housing.

6. In a convenience outlet for electric wiring systems comprising a recessed body member and a back cover plate assembled together to form a hollow housing, said body member having a pair of circular depressions in its front face, and a pair of attachment prong-receiving slots formed in each depression, recesses formed within the body member for supporting the contact members of the outlet to be in alignment with the said slots for making connection with the said prongs, a central bore formed in each circular depression, and a rotating shutter having a similar pair of prong-receiving slots located in each depression, an apertured stud formed on each shutter so that the shutters are arranged to pivot within the said bores by a suitable fastening means, a stop means for limiting the rotation of each shutter to less than and an adjustable torsion spring for each rotating shutter arranged on the pivotal axis of each shutter with one end engaged with the shutter to move therewith while the opposite end of the spring has a tongue portion that is seated within a slotted opening through the back cover plate of the housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,114,258 Tornbloom Apr. 12, 1938 2,154,160 Hamilton Apr. 11, 1939 2,515,003 Hamilton July 11, 1950 

